Both were found stabbed to death at their home in Hermitage Road in July.

The court has given Chang a indefinite hospital order.

Detective Inspector Martin Slevin, from Force CID, led the investigation. Speaking after the court order was imposed, he said: "From a policing point of view, today sees the close of this tragic case but for Chang, his brother and his sister, their agony continues.

"Pin and Quoi Chang lost their lives at the hands of their son who was experiencing a severe bout of mental ill health.

"That day not only saw the senseless loss of life but the devastation of a close and loving family.

"I hope that the end of criminal proceedings will allow the family to continue the long and difficult path to rebuilding their lives in some way."

“Many people who live locally will undoubtedly have been concerned and distressed by today’s events and I’d like to reassure the community that we are doing everything possible to investigate this terrible crime."